This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Cataplexy is a core symptom of narcolepsy, a sleep disorder affecting 1 in 2,000 persons. Cataplexy is most often triggered by strong emotions such as those associated with laughter. Specific Aims: To examine neural systems underlying humor processing in individuals with narcolepsy. Methods: We performed a functional magnetic resonance imaging (fMRI) study in 24 individuals with and without narcolepsy while they watched funny still cartoons. We also examined separately, a subject who experienced a cataplectic attack during the scan and compared both with healthy and with narcolepsy individuals. We measured their subjective ratings of funniness of the cartoons (in all subjects) and cataplectic symptoms (in the patients).